In general, in the case of flip-chip bonding of a light chip, an electrode pad is arranged on either side thereof with a light receiving and emitting portion being sandwiched therebetween so that the light chip is not inclined after being mounted. When such light chip is subjected to flip-chip bonding, large load is applied on a bump corresponding to the electrode pad in the vertical direction with respective to a substrate surface. As a result, there may be a case in which the light chip is distorted and damage is imparted on, for example, the crystal construction of the light receiving and emitting portion of the light chip, thereby deteriorating the reliability of the light chip.
JP-A-H08-153935, for example, discloses as a method for solving such problem, a method according to which a vertical cavity surface emitting laser and a sub mount are bonded with each other with small load.